docs: def _construct_context_for_args(args):
    """Construct a new Context for the parsed arguments.
  
    Args:
      args: the dictionary of magic arguments.
    Returns:
      A new Context based on the current default context, but with any explicitly
        specified arguments overriding the default's config.
    """
    global_default_context = google.datalab.Context.default()
    config = {}
    for key in global_default_context.config:
      config[key] = global_default_context.config[key]
  
    billing_tier_arg = args.get('billing', None)
    if billing_tier_arg:
      config['bigquery_billing_tier'] = billing_tier_arg
  
    return google.datalab.Context(
      project_id=global_default_context.project_id,
      credentials=global_default_context.credentials,
      config=config)